Heater tubes are connected to a heater core, for example, in HVAC systems in motor vehicles. Present day heater core connections often consist of simply brazing the heater tubes to the heater core. Alternatively, the heater core connection can include metal clips that slide over the connection. The problem associated with these connections is that the clips can slide or bend and allow the seal to be broken when the heater tubes are bent or deflected. In the case where the heater tubes are brazed to the heater core, metal fatigue can lead to an early rupture of the connection. The conventional connection of the heater tubes to the heater core holds the tubes in only two directions and provides no effective lateral support.